Modification of plant disease resistance

Abstract

The invention provides methods of increasing resistance to disease in a plant. Also provided are plant steroid biosynthesis enzyme coding sequences, including sequences for squalene synthase, constructs comprising these sequences, plants transformed therewith and methods of use thereof. Methods for producing a plant with increased disease resistance are also provided. In certain aspects of the invention, methods for producing plants transformed with the nucleic acids are provided, the transformed plants exhibiting improved disease resistance.

1 . A method for increasing disease resistance in a plant comprising expressing in the plant a heterologous nucleic acid encoding squalene synthase or sterol methyltransferase. 
     
     
         2 . The method of  claim 1  comprising expressing in the plant a nucleic acid encoding squalene synthase. 
     
     
         3 . The method of  claim 1 , wherein the nucleic acid sequence is operably linked to a promoter functional in a plant cell and wherein the nucleic acid sequence is selected from the group consisting of:
 (a) a nucleic acid sequence comprising SEQ ID NO: 1, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5 or SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:10, or SEQ ID NO:11;   (b) a nucleic acid sequence encoding the polypeptide of SEQ ID NO: 12, SEQ ID NO: 13, or SEQ ID NO: 14;   (c) a nucleic acid sequence having at least 85% sequence identity to the nucleic acid sequence of (a) or (b);   (d) a nucleic acid sequence complementary to the nucleic acid sequence of (a) or (b); and   (e) a nucleic acid sequence that hybridizes to the sequence of (a) or (b) under conditions of 0.15 M NaCl at 70° C.   
     
     
         4 . The method of  claim 3 , wherein the plant is a monocot. 
     
     
         5 . The method of  claim 3  wherein the plant is a dicot. 
     
     
         6 . The method of  claim 5 , wherein the plant is  Arabidopsis thaliana  or  Nicotiana benthamiana.    
     
     
         7 . The method of  claim 3 , wherein the promoter is inducible, organelle-specific, tissue-specific, pathogen-induced, cell-specific, developmentally-specific or constitutive. 
     
     
         8 . The method of  claim 3 , wherein the construct comprises at least one additional sequence chosen from the group consisting of: a regulatory sequence, a selectable marker, a screenable marker, a secretable marker, a leader sequence, and a terminator. 
     
     
         9 . The method of  claim 3 , wherein the construct is inherited from a parent plant of the plant. 
     
     
         10 . The method of  claim 3 , wherein the plant is an R 0  transgenic plant. 
     
     
         11 . The method of  claim 3  wherein resistance to  P. syringae  pv.  glycinea  or  P. syringae  pv.  tomato  is increased. 
     
     
         12 . A method of producing a transgenic plant having enhanced disease resistance comprising introducing into the plant a recombinant DNA construct comprising a promoter functional in plants operably linked to a nucleic acid molecule selected from the group consisting of:
 (a) a nucleic acid sequence comprising the sequence of SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5 or SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:10, or SEQ ID NO:11;   (b) a nucleic acid sequence encoding the polypeptide of SEQ ID NO: 12, SEQ ID NO: 13, or SEQ ID NO: 14;   (c) a nucleic acid sequence having at least 85% sequence identity to the nucleic acid sequence of (a) or (b);   (d) a nucleic acid sequence complementary to a nucleic acid sequence of (a) or (b)   (e) a nucleic acid sequence that hybridizes to the sequence of (a) or (b) under conditions of 0.15 M NaCl and 70° C.   
     
     
         13 . The method of  claim 12 , wherein the plant is a monocot. 
     
     
         14 . The method of  claim 12  wherein the plant is a dicot. 
     
     
         15 . The method of  claim 14 , wherein the plant is  Arabidopsis thaliana  or  Nicotiana benthamiana.    
     
     
         16 . The method of  claim 12 , wherein the promoter is inducible, organelle-specific, tissue-specific, cell-specific, developmentally-specific or constitutive. 
     
     
         17 . The method of  claim 12 , wherein the construct comprises at least one additional sequence chosen from the group consisting of: a regulatory sequence, a selectable marker, a screenable marker, a secretable marker, a leader sequence, and a terminator. 
     
     
         18 . The method of  claim 12 , wherein the construct is inherited from a parent plant of the plant. 
     
     
         19 . The method of  claim 12 , wherein the plant is an R 0  transgenic plant. 
     
     
         20 . The method of  claim 12  wherein resistance to  P. syringae  pv.  glycinea  or  P. syringae  pv.  tomato  is increased.